Year	Number of
1990	143.86
1991	150.65
1992	155.37
1993	160.31
1994	164.96
1995	171.68
1996	180.18
1997	192.72
1998	204.4
1999	223.93
2000	235.45
2001	247.87
2002	259.95
2003	276.09
2004	291.8
2005	309.49
2006	315.14
2007	330.19
2008	334.76
2009	344.5
2010	352.4
2011	351.58
2012	353.17
2013	348.9
2014	341.64
2015	339.55
2016	330.24